The winner is determined by the rules of the deck being used. Winning often requires a player to achieve a certain goal or play a certain card, but every deck is different. Some decks allow players to be eliminated; in these, the winner is usually the last player remaining.
Decks are made either before or during a game. When a card is created it's immediately shown to all players for their approval, halting play if necessary. A card is shuffled into the draw pile if it's accepted unanimously; if not, it's rejected and is set aside without affecting the game. If opposing sides refuse to approve individual cards, multiple cards may be lumped together into a single approve-or-reject vote.
A player draws one card to begin their turn. They may then play an Action and/or a Thing. Their turn is then over and they must discard down to five cards if they have more than five.
If the draw pile is ever empty when someone needs to draw from it, the discard pile is shuffled to form a new one. If the discard pile is also empty, however, players must simply continue without drawing anything.When all the cards are played and there are none left, anyone without cards is out of the game, occasionally resulting in a draw.
When created, special rules are proposed and accepted as normal cards are. However, they are set aside, not shuffled into the draw pile, if they are accepted. They do not count as "cards" for the purposes of interpreting rules.
Beyond that, if one card denies something and another permits it, the denial takes precedence (e.g., "nobody can draw cards" trumps "draw a card".) If cards contradict each other on the same issue, the more specific one takes precedence (e.g., "this player's hand size is seven" trumps "everyone's hand size is four".) Finally, if contradictory cards are equally specific, the last-played one takes precedence.
Special rules count as cards for conflict resolution purposes. As such, they always take precedence over the basic rules, but they may be overruled by other cards.